Adaptive Sliding Mode Control for Active Suspensions of IWMD Electric Vehicles Subject to Time Delay and Cyber Attacks

This paper addresses the control problem for active suspensions of the in-wheel motor driven electric vehicle with consideration of time delay and cyber attacks. The main purpose is to develop an adaptive sliding mode control (SMC) method to improve the suspension performances by handling the issues of time delay and cyber attacks. Firstly, by considering a dynamic vibration absorber to mitigate vibrations, an active suspension model is constructed, in which both the spring dynamic nonlinearity and the damper dynamic segmentation are approximated by the Takagi-Sugeno fuzzy model. Secondly, by introducing an integral-type sliding surface, sufficient conditions are developed to ensure the sliding motion satisfies the asymptotical stability and desired performance requirements despite the occurrence of time delay. Based on the reachability to the sliding surface, a SMC approach is developed such that the closed-loop suspension system can achieve the desired performances of the sliding surface. For a better calculation of the controller gains, the controller design condition is converted to an optimization problem. Finally, various simulation tests are implemented to verify the merits of the proposed adaptive control method.